Added material to the BeyondFacts Lab (#1180)

app/MindWork AI Studio/Assistants/BeyondFactsLab/BflTranscriptLocation.cs

@@ -0,0 +1,57 @@
+using AIStudio.Tools.Media;
+
+namespace AIStudio.Assistants.BeyondFactsLab;
+
+/// <summary>
+/// Where the transcript of a recording waits while the lab turns it into material, cf. PersistentMediaTranscript.
+/// </summary>
+/// <remarks>
+/// The lab keeps only the filtered text of a transcript, as the text of the material. The transcript itself lies in
+/// a folder of its own below media-staging of the data directory, which the lab deletes once it has read the
+/// transcript; whatever a crash leaves there, TranscriptStagingCleanupService removes with the next start. Backups
+/// leave that folder out.
+/// </remarks>
+/// <param name="dataDirectory">The data directory of AI Studio.</param>
+internal sealed class BflTranscriptLocation(string dataDirectory) : IMediaTranscriptLocation
+{
+    /// <summary>
+    /// The folder of the data directory for transcripts on their way, shared with the chat; see TranscriptStagingCleanupService.
+    /// </summary>
+    private const string STAGING_DIRECTORY_NAME = "media-staging";
+
+    /// <summary>
+    /// The name of the transcript in its folder.
+    /// </summary>
+    private const string TRANSCRIPT_FILE_NAME = "transcript.md";
+
+    /// <summary>
+    /// Gets the folder of this transcript, which no other one shares.
+    /// </summary>
+    public string FolderPath { get; } = Path.Combine(dataDirectory, STAGING_DIRECTORY_NAME, $"bfl-{Guid.NewGuid():N}");
+
+    /// <inheritdoc />
+    public Task<MediaTranscriptSlot> ResolveAsync(string mediaPath, CancellationToken token)
+    {
+        var path = Path.Combine(this.FolderPath, TRANSCRIPT_FILE_NAME);
+        return Task.FromResult(new MediaTranscriptSlot(path, path));
+    }
+
+    /// <summary>
+    /// Deletes the transcript with its folder, without failing.
+    /// </summary>
+    /// <returns>False when the folder could not be deleted; the next start removes it.</returns>
+    public bool TryDelete()
+    {
+        try
+        {
+            if (Directory.Exists(this.FolderPath))
+                Directory.Delete(this.FolderPath, true);
+
+            return true;
+        }
+        catch (Exception exception) when (exception is IOException or UnauthorizedAccessException)
+        {
+            return false;
+        }
+    }
+}